Numerous treatments for HIV are known in the art, and among other pharmaceutically active compounds, reverse transcriptase inhibitors have provided significant therapeutic effect to many HIV infected patients. For example, lamivudine (3TC) or zidovudine (AZT) are relatively well tolerated antiretroviral drugs. However, numerous viral strains have recently emerged with marked resistance against these compounds. To overcome resistance to at least some degree, new nucleoside-type inhibitors may be administered (alone or in combination with other nucleoside-type inhibitors), and exemplary alternative drugs include stavudine (d4T), didanosine (ddI), Combivir™ (brand for a combination of lamivudine and zidovudine), and Trizivir™ (brand for a combination of 3TC, AZT, and abacavir).
Unfortunately, development of resistance to one nucleoside-type inhibitor is often accompanied by the development of a degree of resistance to another nucleoside-type inhibitor, frequently necessitating a switch to a different class of drug. In such cases, a patient may receive a protease inhibitor (e.g., saquinavir, indinavir, nelfinavir, etc.), typically in combination with other anti retroviral agents. However, the relatively complex administration regimen of such combinations often proves an organizational and financial challenge to many patients, and compliance is frequently less than desirable.
More recently, HIV treatment has focused on combination therapies that involve the administration of nucleoside reverse transcriptase inhibitors with protease inhibitors and with non-nucleoside reverse transcriptase inhibitors, and triple combinations of nucleoside reverse transcriptase inhibitors, non-nucleoside reverse transcriptase inhibitors and protease inhibitors. Unfortunately, combination therapies of protease inhibitors with nucleoside reverse transcriptase inhibitors are often poorly tolerated and frequently lead to premature termination of the therapy. Therefore, most current combination treatments include a combination of nucleoside reverse transcriptase inhibitors and non-nucleoside reverse transcriptase inhibitors.
Non-nucleoside-type inhibitors (e.g., nevirapine, delavirdine, and efavirenz) are a structurally inhomogeneous group of compounds that are thought to bind in a non-nucleoside pocket of the reverse transcriptases. They significantly increase antiviral efficacy when co-administered with nucleoside-type inhibitors. While the non-nucleoside-type inhibitors seem to provide a promising new class of antiviral drugs, several disadvantages still remain. The cost of currently-known non-nucleoside-type inhibitors is relatively high, and a single mutation in the viral reverse transcriptases can induce a cross resistance against a wide class of non-nucleoside reverse transcriptase inhibitors. Therefore, there is an urgent to provide new non-nucleoside reverse transcriptase inhibitors that have potent antiviral effects, particularly against HIV mutant strains that exhibit resistance against currently-known non-nucleoside reverse transcriptase inhibitors.
The HIV virus has a relatively high frequency of mutation, which often leads to drug resistance to current treatments. Studies have been carried out to identify the mutation spectrum in the RT proteins of viruses isolated from patients who had failed therapies involving at least one NNRTI, and the results showed that the mutant K103N was the most predominant for patients taking efavirenz, while Y181C was predominant for patients taking nevirapine. Other single mutations included K101E, G190S/A/E and Y188L/C. Some of the most prevalent double mutations in patients failing efavirenz include K103N-P225H, K103N-V108I, K103N-K101Q, K103N-L100I, K103N-F227L, V106I-Y188L, K103N-Y188L and K103N-G190A. There is a need to provide new compositions and methods for the inhibition of these and other mutant reverse transcriptases.
The present application is related to work previously disclosed in commonly owned applications PCT/US02/26186, filed Aug. 23, 2002, unpublished, and PCT/US03/27433, filed Aug. 22, 2003, which was published as WO 2004/030611 on Apr. 15, 2004. U.S. Pat. No. 5,939,462 to Connell et al. discloses a large number of substituted heterocycles, useful as NPY5 receptor antagonists, some of which are S-triazolyl mercaptoacetanilides similar to general structure 1 below. Simoneau et al., in international patent publication WO 2004/050643, disclose tetrazoles and a few triazoles having structures similar to those of the present invention, having reverse transcriptase inhibitory activity.